Harvest time should be the single most exciting part of a cannabis grow. You have waited patiently, loyally tending your buds for many weeks. While many impatient beginner growers have the tendency to harvest early, you should resist this temptation. THC levels are determined by age and development of the buds. Remember, cannabis growth stops at harvest. If you harvest too early, you cannot replace whatever THC content you have missed out on. On the other hand, waiting too long to harvest can lead to the degradation of THC. Paying close attention to visual characteristics of the plant, such as pistol and trichome development, will ensure an appropriate harvest time.
Pistils and Trichomes
A simple way to monitor plant development is to keep an eye on its pistils. These resin-covered female organs resemble sticky hairs and change in appearance during a growth cycle. Starting out mostly clear, pistils transition to solid white, then an orange hue, and eventually into dark red or brown. An orange hue color can indicate your plants are nearing maturity. However, this is a relatively inaccurate method when choosing a particular harvest time. Only use it for rough estimates.
What you should really be monitoring is trichome development. Much smaller and more delicate than pistils, these mushroom shaped crystals are nearly invisible to the naked eye. For this reason, you will need a jeweler’s loupe or handheld magnifier to examine trichome development. Some even opt to use digital microscopes for an up-close view. You want to have at least 50-100x magnification.
Like pistils, trichomes also start out clear but turn to an opaque, milky white color. When most of your trichomes have reached this milky hue, the crop is nearing harvest time. Some amber colored trichomes will also have appeared. The earlier you harvest your crop, the more uplifting and cerebral its effects will be. Allowing the plant to develop further will lead to the degradation of THC into CBN (cannabinol). This will create more of a sedative, body-centered high.
By the time you are 1-2 weeks into a grow, you should be analyzing your trichomes daily. Depending on personal preference and the particular strain, you may decide to harvest your buds as early as possible.
Flushing the Plants
Once you are satisfied with bud growth and trichome development, it is time to flush the plants. The goal here is to rid the plants of all excess nutrients, so they are forced to live on stored food reserves. These sugars, starches, and other chemicals should be considered unwanted toxins. This can lead to harsher smoke with poor taste, and can actually act as a fire retardant.
You want to flush the plants during the final two weeks of growth. A thorough saturation of the plant will dissolve nutrients and allow them to leave the container. Allow the plant to sit long enough for salt particles to dissolve before a second saturation. You can test for the presence of nutrients by tasting one of the leaves. You are looking for a clean, watery flavor. If the taste is bitter, chemicals and nutrients are likely still present.
Perform a final flush during the final two days before harvest, and provide a low humidity environment for the remaining time. Dry air allows for higher THC resin production.
Drying and Curing
When you decide to harvest your crop, make sure do it early in the morning. Ideally, you would harvest the buds right before the grow lights normally would have kicked on. At night, when the plants are under no direct light, starches and other foods are stored in the plant roots. Harvesting early in the morning ensures any excess nutrients not removed during flushing are stored in the roots rather than in the buds. Your buds will burn and smoke more smoothly. You are ready to remove each branch for drying.
It is necessary to allow your cannabis crop time to dry properly. Plants should dry for at least 5-7 days. Drying your buds for less than five days creates a high risk for mold growth. An ideal environment would be controlled at around 75 degrees Fahrenheit, with 50% humidity. Allowing enough drying time also allows once acidic THC molecules to neutralize and helps activate its psychoactive properties. After 5-7 days your buds should appear mostly dry, but stems should remain somewhat flexible. You can expect your buds to lose up to three-quarters of their weight during the drying process.
At this point, you can do a quick basic trim of your buds and transfer them into air-tight containers for curing. Trimming bud is an artform, and hand trimmed bud can come at a premium, but, many growers claim there is less trichome loss with the modern trimming machines. Chances are, if your grow is just a personal or small scale, you’ll end up trimming a few days with your employees or friends. An oxygen free environment allows good anaerobic bacteria to thrive, consuming leftover sugars. Make sure you pack the containers fairly loosely to allow for fresh oxygen circulation. While there is no limit to how long you can cure your cannabis buds, a general rule of thumb is at least two weeks. You should open the container periodically to monitor dryness and to introduce fresh air into the container.
The curing process allows you to store the buds for long periods of time without fears of THC degradation or mold growth. Curing also plays a major role in the smoke quality and taste of the buds. A slow, controlled cure preserves terpenes—pungent oils that with distinctive flavors.
You should not take the importance of harvest time lightly. While you have been working hard to grow healthy buds, the hard work is not done. Attention to detail is a must, and plants need to be closely monitored on a daily basis. Know your desired THC content and plan accordingly.
Invest in a quality handheld magnifier. Magnifying lenses to attach to your cell phone are also available. This is a vital tool and will allow you to precisely monitor plant and development.
Remain patient and allow the full 5-7 days for drying and at least two weeks for curing. You have already waited several weeks; you can wait three more. Adequate dry time will ensure your buds are healthy and mold free. A longer cure time will create a smoother, less harsh smoke.